Power transfer

[mjoekingz28]

How do the various forms of racing get the engine power to the wheels? I.e. rally car= 4wd transfer case- cv axles..........

I am mostly interested in how a top fuel dragster get the power from the crank to the rear tires. I.E- crankshaft-flywheel-clutch-transmission-driveshaft-differential

 

[OVERKILL]

http://www.popularmechanics.com/cars/a12596/anatomy-of-a-top-fuel-dragster/

Quote:
A five-disc dry clutch is the only link between the engine and the locked rear end—there's no transmission. "The clutch is the lifeline of the car," Oberhofer says, because it regulates wheelspin by gradually engaging and slipping as the car moves down the track. A hydraulically motivated throw-out bearing operates off a simple timer (computer controls are illegal). The clutch is tuned according to track conditions. If it engages too quickly, the tires will spin, but if it's too lazy, the car won't accelerate as fast as possible. The discs get so hot that at least two of them are welded together by the run's end.

 

[Shannow]

That's it...

I became unbeatable on the drag racing game on the Atari back in the day after I learned that's how they work.

Hold it flat, and tap the clutch continually to control slip.

 

[punisher]

"He (Patrick Hale) got some data logger info from Lee Beard for Steve Torrence’s 3.775 @ 328.38 mph run. He made some calculations off the time slip and the logger data.
They said the car was about 50 lbs lighter at the finish line than the starting line due to the fuel burned in the run. 2320 lbs min weight.
The highest G force is about 2.5 sec into the run. (4.8 g) :shock:

Time into run = 1 sec
Engine RPM = 7890
Driveshaft RPM = 2775
G meter (g’s) = 3.75
Fuel flow (GPM) = 60.7
Manifold boost (PSI) = 47
Ignition Timing (deg) = 36.5
Total Aero Drag HP = 70
Clutch slippage HP = 4607
Inertia HP = 88
Acceleration HP = 2118
Friction HP = 178
Calculated Engine HP = 7061


Time into run = 2.5 sec
Engine RPM = 7075
Driveshaft RPM =6275
G meter (g’s) = 4.8
Fuel flow (GPM) = 82.5
Manifold boost (PSI) = 48.5
Ignition Timing (deg) = 60.5
Total Aero Drag HP = 1142
Clutch slippage HP = 1061
Inertia HP = 567
Acceleration HP = 5939
Friction HP = 661
Calculated Engine HP = 9371


Time into run = 3.775 sec
Engine RPM = 8425
Driveshaft RPM =8425
G meter (g’s) = 2.0
Fuel flow (GPM) = 82.5
Manifold boost (PSI) = 60.5
Ignition Timing (deg) = 51.0
Total Aero Drag HP = 2940
Clutch slippage HP = 0.0
Inertia HP = 628
Acceleration HP = 3519
Friction HP = 833
Calculated Engine HP = 7920

Hale figured Antron Brown’s 3.071 ET was 10,100 HP."

What I took away from this- The clutch absorbs/dissipates 4600 HP at the one second mark before lockup. It takes almost 3K HP to overcome aero drag on the top end. The car is still accelerating at 2g at the end of the run.

 

[DeepFriar]

Man, reading about those stats never gets old! It's like somebody describing nuclear fusion.

 

[Oldmoparguy1]

Mind blowing!

 

[02SE]

One thing to keep in mind: Due to the proprietary nature of data acquisition on a TF/D, info posted on the 'net may or may not be entirely accurate..

 

[bdcardinal]

Originally Posted By: 02SE
One thing to keep in mind: Due to the proprietary nature of data acquisition on a TF/D, info posted on the 'net may or may not be entirely accurate..

That was what I was thinking. I know there are some teams in other racing series that will purposefully give incorrect info to throw off competitors.

 

[mjoekingz28]

Lying is a sin.

 

[bdcardinal]

Originally Posted By: mjoekingz28
Lying is a sin.


Not in motorsports.

 

[A_Harman]

Originally Posted By: 02SE
One thing to keep in mind: Due to the proprietary nature of data acquisition on a TF/D, info posted on the 'net may or may not be entirely accurate..

I can believe that, but it is interesting to see the parameters that are monitored.

 

[02SE]

Originally Posted By: A_Harman


I can believe that, but it is interesting to see the parameters that are monitored.


Some of the parameters, anyway. Most teams monitor far more than that. If this stuff wasn't proprietary, it might make interesting reading for some.

I'll just say it's a very complicated puzzle to get right.

 

[04SE]

Question on the ignition timing? 50* - 60*???? Holy cow!

I thought they toasted the plugs with in a second or so and were 'dieseling' for ignition?

EDIT: just read the article and it says dieseling in 3.5 seconds

 

[userfriendly]

Think of nitro fuel as your double based gun powder. It takes heat to release the oxygen that sustains the burn.
A fuel that brings it's own O2 supply. Late burning, needs lots of advance to put the cylinder pressure where it can do the most work.
Unfortunately, the charge is still going at it when it comes time to open the exhaust valve.
Now a two stroke nitro engine, like you little model aircrafts bored out to 500 cubic inches...

 

[punisher]

Originally Posted By: used_0il
Think of nitro fuel as your double based gun powder. It takes heat to release the oxygen that sustains the burn.


That dovetails into something that I always thought was interesting. The blower/supercharger on a nitro burner is not used in the same capacity as a blower on a gasoline or alky engine. The main thing a blower is used for on a nitro engine is to supply heat to maintain ignition temps and combustion of the nitro. The amount of actual O2 content is secondary to the actual pressure, and the heat contained, in the compressed air.